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81.
This study investigated the developmental continuity, stability, and organization of infants' behavioral response to mild stress from 1 to 3 months of age. Changes in infant stress reactivity were expected to coincide with a suspected neurobiological shift around the 2nd month. A total of 53 infants and their mothers participated in this study. At 1 and 3 months, infants' stress reactivity to mild perturbation was assessed by withdrawing a pacifier during nonnutritive sucking. Infant baseline heart rate activity and maternal reports of infant temperament were also obtained. Focusing on facial and vocal negativity, behavioral measures of infant reactivity to pacifier withdrawal were coded from videos. Results showed that developmental continuity and individual instability characterized changes in infant stress reactivity over the 2nd‐month transition. Developmental reorganization was also evidenced by changes in the direction and magnitude of infant stress reactivity in relation to baseline heart period and maternal temperament ratings, respectively. These findings provide direct supporting evidence for the contention that changes in infant stress reactivity to mild perturbation may be a function of developmental shifts in underlying neurobiological mechanisms in early infancy. 相似文献
82.
A parity walk in an edge-coloring of a graph is a walk along which each color is used an even number of times. A parity edge-coloring (respectively, strong parity edge-coloring) is an edge-coloring in which there is no nontrivial parity path (respectively, open parity walk). The parity edge-chromatic number p(G) (respectively, strong parity edge-chromatic number $\widehat{p}(G)$ ) is the least number of colors in a parity edge-coloring (respectively, strong parity edge-coloring) of G. Notice that $\widehat{p}(G) \ge p(G) \ge \chi'(G) \ge \Delta(G)$ for any graph G. In this paper, we determine $\widehat{p}(G)$ and p(G) for some complete bipartite graphs and some products of graphs. For instance, we determine $\widehat{p}(K_{m,n})$ and p(K m,n ) for m≤n with n≡0,?1,?2 (mod 2?lg?m?). 相似文献
83.
System characteristics of a redundant repairable system with two primary units and one standby are studied from a Bayesian viewpoint with different types of priors assumed for unknown parameters, in which the coverage factor is the same for an operating unit failure as that for a standby unit failure. Times to failure and times to repair of the operating and standby units are assumed to follow exponential distributions. When times to failure and times to repair with uncertain parameters, a Bayesian approach is adopted to evaluate system characteristics. Monte Carlo simulation is used to derive the posterior distribution for the mean time to system failure and the steady-state availability. Some numerical experiments are performed to illustrate the results derived in this paper. 相似文献
84.
Cox and Oakes (1984) claimed that a model satisfies the accelerated lifetime (AL) model and the proportional hazards (PH) model iff it is Weibull. Doksum and Nabeya (1984) constructed a family of analytic non Weibull survival functions that satisfies both the PH and AL models. We further study the relationship between the PH, AL, Lehmann, and Weibull models without the restriction of absolute continuity. 相似文献
85.
Jason C. Hsu 《统计学通讯:理论与方法》2013,42(9):2009-2028
There are three types of multiple comparisons: all-pairwise multiple comparisons (MCA), multiple comparisons with the best (MCB), and multiple comparisons with a control (MCC). There are also three levels of multiple comparisons inference: confidence sets, subset comparisons, test of homogeneity. In current practice, MCA procedures dominate. In correct attempts at more efficient comparisons, in the form of employing lower level MCA procedures for higher level inference, account for the most frequent abuses in multiple comparisons. A better strategy is to choose the correct type of inference at the level of inference desired. In particular, very often the simulataneous comparisons of each treatment with the best of the other treatments (MCB) suffice. Hsu (1984b) gave simultaneous confidence intervals for θi ? maxj≠iθj having the simple form [? (Yi ?maxj≠i Yj ? C) (Yi?maxj≠i Yj + C)+]. Those intervals were constrained, sothat even if a treatment is inferred to be the best, no positive bound on how much it is better thatn the rest is given, a somewhat undesirable property. In this article it is shown that by employing a slightly larger critical value, the nonpositivity constraint on the lower bound is removed. 相似文献
86.
87.
The five steps of the theory of constraints (TOC) emphasize exploiting constraints in order to increase the throughput of a system. The product mix decision is one application of the TOC five steps. However, these steps were considered to be implicit or incomplete, the criticism being that they result in deriving an infeasible solution when a plant has multiple resource constraints. This paper follows the essence of these five steps and presents an explicit algorithm to address the problem. When testing its effectiveness by using a dual-simplex method with bounded variables, this algorithm gives the same result in each iteration. 相似文献
88.
This article studies a single-machine scheduling with deteriorating jobs and aging effects under an optional maintenance activity. We assume that after maintenance activity, the machine will revert to its initial condition and the aging effects will start anew. Moreover, due to the restriction of budget of maintenance, the limitation of the maintenance frequency on the machine is assumed to be known in advance. The optional maintenance activity of this study means that the starting time of the maintenance activity is unknown in advance. It can be scheduled immediately after the processing of any job that has been completed. Therefore, the planner must to make decision on whether or when to schedule the maintenance activity during the scheduling horizon to optimal the performance measures. The objective is to minimize the makespan. We first show that the addressed problem is NP-hard in the strong sense. Then a fully polynomial-time approximation scheme (FPTAS) for the proposed problem is presented. 相似文献
89.
The group ranking problem involves constructing coherent aggregated results from users’ preference data. The goal of most group ranking problems is to generate an ordered list of all items that represents the user consensus. There are, however, two weaknesses to this approach. First, a complete list of ranked items is always output even when there is no consensus or only a slight consensus. Second, due to similarity of performance, in many practical situations, it is very difficult to differentiate whether one item is really better than another within a set. These weaknesses have motivated us to apply the clustering concept to the group ranking problem, to output an ordered list of segments containing a set of similarly preferred items, called consensus ordered segments. The advantages of our approach are that (i) the list of segments is based on the users’ consensuses, (ii) the items with similar preferences are grouped together in the same segment, and (iii) the relationships between items can be easily seen. An algorithm is developed to construct the consensus of the ordered segments from the users’ total ranking data. Finally, the experimental results indicate that the proposed method is computationally efficient, and can effectively identify consensus ordered segments. 相似文献
90.
Tung-Yang Ho Chun-Nan Hung Lih-Hsing Hsu 《Journal of Combinatorial Optimization》2007,14(2-3):275-294
A graph G=(V,E) is Hamiltonian connected if there exists a Hamiltonian path between any two vertices in G. Let P
1=(u
1,u
2,…,u
|V|) and P
2=(v
1,v
2,…,v
|V|) be any two Hamiltonian paths of G. We say that P
1 and P
2 are independent if u
1=v
1,u
|V|=v
|V|, and u
i
≠v
i
for 1<i<|V|. A cubic graph G is 2-independent Hamiltonian connected if there are two independent Hamiltonian paths between any two different vertices of G. A graph G is 1-Hamiltonian if G−F is Hamiltonian for any F⊆V∪E with |F|=1. A graph G is super 3*-connected if there exist i internal disjoint paths spanning G for i=1,2,3. It is proved that every super 3*-connected graph is 1-Hamiltonian. In this paper, we prove that every cubic 2-independent Hamiltonian connected graph is also
1-Hamiltonian. We present some cubic 2-independent Hamiltonian connected graphs that are super 3*-connected, some cubic 2-independent Hamiltonian connected graphs that are not super 3*-connected, some super 3*-connected graphs that are not 2-independent Hamiltonian connected, and some cubic 1-Hamiltonian graphs that are Hamiltonian
connected but neither 2-independent Hamiltonian connected nor super 3*-connected.
Dedicated to Professor Frank K. Hwang on the occasion of his 65th birthday.
This work was supported in part by the National Science Council of the Republic of China under Contract NSC 94-2213-E-233-011. 相似文献